1. Field of the Invention
The invention relates to liquid hydrocarbon fuel compositions. More particularly it relates to fuel compositions containing a detergent additive.
2. Description of the Prior Art
It is well known to those in this art that liquid hydrocarbon combustion fuels, such as fuel oils and gasolines, tend to exhibit certain deleterious characteristics, either after long periods of storage or under actual operational conditions. Gasolines, for example, in operational use tend to deposit sludge and varnish at various points in the power system, including carburetor and intake valves. It is desirable, therefore to find a means for improving liquid hydrocarbon fuels by lessening their tendency to leave such deposits.
Recent interest in the use of detergents for liquid hydrocarbon fuels has lead to the employment of non-metallic compounds. The advantageous feature of these non-metallic detergents is that they do not leave ashy deposits in an engine as do the metallic detergents. Such detergents include alkyl-substituted organic compounds, some of them polymeric in nature, one particular class containing amide or imide groups. The optimum activity of many of these detergents appears to be at low or moderate temperatures only.
U.S. Pat. Nos. 3,172,892; 3,219,666; 3,272,746; 3,281,428 and 3,445,386 are directed broadly to polyalkenylsuccinictype ashless additives. The first four patents disclose additives in which the alkenyl group is derived from the poly-C.sub.4 olefins. The last patent teaches an alkenyl derived from polypropylene having a molecular weight of from about 500 to about 3000. It also teaches the use of the additive disclosed therein as a fuel detergent.
U.S. Pat. No. 3,649,229 teaches a fuel containing a detergent amount of a Mannich base product made using, among other reactants, an alkenylsuccinic compound.